The present invention relates to an apparatus for absorbing a sudden shock loading or jerk applied to a cable and, in particular, to an apparatus for absorbing the jerk applied to a cable used to operate a looping car which is employed to provide a temporary storage of a web of material during the processing thereof.
In the processing of a continuous web of material, such as steel, it is occasionally necessary to temporarily store a portion of the web in order that distinct lengths of the web may be joined so that the process steps may occur continuously. For example, in the steel industry, it is expedient that certain processes such as cleaning (or pickling) or the electrogalvanizing process, run on a continuous sheet of material. As such, it is necessary that a storage area be provided to accommodate excess sheet material which may be processed while the entry end is stopped for welding individual strips together or while the exit end is stopped for separating and individually bundling the sheet products.
In a commonly employed system, a series of multiple tiers of horizontal tracks are provided. A wheeled vehicle, or looper car, is configured to ride on the uppermost and lowermost of each such tracks. Each of the looper cars carries a horizontal roll whose axis is perpendicular to the direction of travel of the strip. Stationary rolls are provided in intermediate levels to provide additional storage. The strip is successively wrapped around the looper cars and the stationary rolls in order that when the looper cars are at the ends of their tracks a maximum amount of sheet may be stored. When the mill is prepared to accommodate the stored strip, the looper cars are drawn toward the stationary rolls on the opposite ends of their respective tracks by the action of the strip on the looper cars and a minimum amount of strip is maintained in the storage region.
To store additional strip material in the storage area, the looper cars are each moved toward the ends of their respective tracks and against the action of the strip by means of cables which are provided from a motorized winch means. In the past, to affix the cables to the looper cars, the cables were wound about a vertical pipe affixed to each looper car and bolted to a support affixed to such pipes. The action of the respective winches on the cables causes the looper cars to move to the ends of the tracks against the force of the strip thereby drawing an increased length of strip into the storage area.
It will be readily appreciated that the cycle of filling and emptying the storage area by means of the releasing and the regathering of the cables which move the looper cars must occur frequently and rapidly as the strip under process is continuously moving at a high linear speed. As such, the cables affixed to the looper cars are frequently being pulled suddenly and rapidly by the winch. Such rapid pulling or jerking of the cables has been definitively proven to cause the premature failure of such cables. Of course, when such cables fail, the entire processing line must be stopped to allow replacement of the broken cable. It is apparent that the total cost of halting production of an entire line to replace a cable is staggering. Also, the cost of replacement cable and the manpower to replace it is considerable. Accordingly, a means of preventing premature cable failure due to the jerk loading of such cables is most necessary.
As such, the present invention is directed toward an apparatus for absorbing the jerk loading applied to a cable which overcomes, among others, the above-discussed problems and provides an effective, low-cost apparatus for absorbing shock in a cable to prolong its life.